Re: [PERFORM] What kind of performace can I expect and how to measure?

2004-08-02 Thread Joost Kraaijeveld
Hi Merlin,

 The 9206 ms time is what the database actually spent 
 gathering the data and sending it to you.  This is non-negotiable unless you bump up
 hardware, etc, or fetch less data.  This time usually scales linearly
 (or close to it) with the size of the dataset you fetch.

 The 40638 ms time is pgAdmin putting the data in the grid.  This time
So it take PostgreSQL 9206 ms to get the data AND send it to the client. It than takes 
PGAdmin 40638 ms to display the data?

 solution).  In the meantime, I would suggest using queries to refine
 your terms a little bit...(do you really need to view all 80k 
 records at once?).
The application is build in Clarion, a 4 GL environment. We do not have any influence 
over the query it generates and executes.


Groeten,

Joost Kraaijeveld
Askesis B.V.
Molukkenstraat 14
6524NB Nijmegen
tel: 024-3888063 / 06-51855277
fax: 024-3608416
e-mail: [EMAIL PROTECTED]
web: www.askesis.nl 

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Re: [PERFORM] What kind of performace can I expect and how to measure?

2004-08-02 Thread Merlin Moncure
 Hi Merlin,
 
  The 9206 ms time is what the database actually spent
  gathering the data and sending it to you.  This is non-negotiable
unless
 you bump up
  hardware, etc, or fetch less data.  This time usually scales
linearly
  (or close to it) with the size of the dataset you fetch.
 
  The 40638 ms time is pgAdmin putting the data in the grid.  This
time
 So it take PostgreSQL 9206 ms to get the data AND send it to the
client.
 It than takes PGAdmin 40638 ms to display the data?

That is correct.  This is not a problem with pgAdmin, or postgres, but a
problem with grids.   Conceptually, SQL tables are an in an unordered,
infinite space and grids require an ordered, finite space.  All 4GLs and
data managers have this problem.  The real solution is to refine your
query in a meaningful way (80k rows is more than a human being can deal
with in a practical sense).  If you can't do that, install an arbitrary
limit on the result set where performance breaks down, could be 10-100k
depending on various factors.

To simulate a finite, ordered, dataset, pgAdmin takes all the result
data and puts it in GUI controls are not designed to hold 100k rows
data...this is a design compromise to allow editing.

Merlin






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Re: [PERFORM] What kind of performace can I expect and how to

2004-08-02 Thread Scott Marlowe
On Mon, 2004-08-02 at 06:21, Joost Kraaijeveld wrote:
 Hi all,
 
 My system is a PostgreSQL 7.4.1 on i686-pc-linux-gnu, compiled by GCC gcc (GCC) 
 20020903 (Red Hat Linux 8.0 3.2-7). It has a Pentium III-733 Mhz with 512 MB ram. It 
 is connected to my workststation (dual XEON 1700 with 1 Gb RAM) with a 100 Mb 
 switched network.
 
 I have a table with 31 columns, all fixed size datatypes. It contains 88393 rows. 
 Doing a select * from table with PGAdmin III in it's SQL window, it takes a total 
 of 9206 ms query runtime an a 40638 ms data retrievel runtime.

This means it took the backend about 9 seconds to prepare the data, and
40 or so seconds total (including the 9 I believe) for the client to
retrieve and then display it.

 Is this a reasonable time to get 88393 rows from the database?

Depends on your row size really.  I'm certain you're not CPU bound if
you've only got one hard drive.  Put that data on a 20 way RAID5 array
and I'm sure it would come back a little quicker.

 If not, what can I do to find the bottleneck (and eventually make it faster)?

The bottleneck is almost always IO to start with.  First, as another
drive and mirror it.  Then go to RAID 1+0, then add more and more
drives.

Read this document about performance tuning:

http://www.varlena.com/varlena/GeneralBits/Tidbits/perf.html




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